Circulatory System Cont. + Small Lymphatic System and Cancer
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24 terms
Terms | Definitions |
|---|---|
 Factors that cause Vasodilation | Increase in CO2, extracellular K+ Decrease in O2, pH NO Histamine Adenosine Epinephrine: only when acting on Beta-2 receptors: results in relaxation of smooth muscle (arterioles in skeletal muscles) |
| NO | -potent vasodilator synthesized when the [K+] -NO as a gas will diffuse from one cell to another and act locally to cause vasodilation -involved in variety of responses to stimuli and trauma |
| Histamine | -Released by mast cells in excessive response to allergies -increased blood flow, increased capillary permeability to cause swelling |
| Adenosine | -Released with high metabolism and decrease in O2 -Important in heart skeletal muscles and liver -Increase blood flow so that when there is lot of activity, adenosine is released and there will be vasodilation and increase in blood flow |
| NE's effect on vasoconstriction E's effect on vasoconstriction | NE acts on Alpha-1 receptors E acts on Alpha-1 or B-2 to either constrict or dilate depending |
| Endothelin | Causes vasoconstriction; released by endothelin cells locally |
| Angiotesin II hormone | -all arteries have receptors for angiotesin so it will increase in vasoconstriction in all vessels -many treatments for hypertension either block production of angiotensin II or block the receptors for angiotensin II |
| How is vasoconstriction tonically controlled? | Autonomic system has tonic control so that there is a certain frequency of APs that release a certain amount of E and have a certain degree of vasoconstriction via Alpha-1 receptors |
| How does E activate Beta-2 receptors rather than Alpha-1 receptors? | by having a higher concentration of E than NE |
| What is the main point of Circulation? | Capillary Exchange (or gases and h2o) |
| Simple Diffusion in Capillaries | only gases (O2, CO2) since they are soluble across the bilayer and can diffuse |
| Bulk Flow in Capillaries | way by which H20 and small molecules can diffuse across the capilaries into tissues -pores aren't large eoungh to allow proteins in plasma across |
| What forces regulate Bulk Flow | 1. Hydrostatic Pressure 2. Osmotic Pressure |
| hydrostatic pressure | equals difference between hydrostatic pressure in capillaries and the hydrostatic pressure in the interstitial fluid |
| Is the hydrostatic pressure usually higher int he capillaries or in the interstitial fluid? | Hydrostatic pressure is usually higher in the capillaries than in the interstitial fluid H20 flow is usually outward due to hydrostatic pressure |
| Osmotic pressure (aka Colloid Pressure) | contributed by impermeable solutes (plasma proteins) Since only found in plasma, this only flows into capillaries and out of the interstitial fluid |
| What is the main contributor of plasma proteins to osmotic pressure? | albumin |
| Net flow equation for Fluid exchange in capillaries | Net Flow=K(Pcapillary-Pinterstitial fluid)-(Πcapillary-Πinterstial fluid) Where P= Hydrostatic Pressure Where Π= Osmotic Pressure |
| When hydrostatic pressure drops along the capillaries so that osmotic pressure increases and there is a net absorption at the end of a capillary bed but net filtration at the beginning of the capillary, what does this cause? | Net loss of fluid into interstitial fluid and this is picked up by the lymphatic system |
| Does hydrostatic pressure increase or decrease due to vasodilation? what does this do to filtration? what does this then do to the interstitial water? | increase increase filtration=> excess water in H2O in interstitial which leads to edema -occurs in high altitudes |
| How could you move water from the interstitial area into the capillaries and then into the kidneys to be urinated out | by wrapping yourself in tight bandages in order to increase hydrostatic pressure so that water will diffuse into the capillaries and into the kidney then out for urination |
| Lymphatic System | -picks up excess fluid that is not taken up in the capillaries -excess fluid enters lymph vessels which eventually return this fluid to the circulation |
| Metastasis in Cancer | can spread by 1. entering the blood 2. entering lymphatic system |
| Elephantitis | parasites that plug up the lypathics. Results in swelling of the legs, arms and scroumex |
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